insane

[in-seyn] /ɪnˈseɪn/
adjective
1.
not sane; not of sound mind; mentally deranged.
2.
of, pertaining to, or characteristic of a person who is mentally deranged:
insane actions; an insane asylum.
3.
utterly senseless:
an insane plan.
Origin
1550-60; < Latin insānus. See in-3, sane
Related forms
insanely, adverb
insaneness, noun
pseudoinsane, adjective
Synonyms
1. demented; lunatic, crazed, crazy; maniacal. 3. foolish, irrational. See mad.
Examples from the web for insane
  • For them, going to extremes that may seem insane was actually a logical progression.
  • insane with fury, he murdered his family-then turned his sword upon himself.
  • Take a looks at relative salaries, though, and it isn't as insane as it appears.
  • The good doctor is also completely insane if he actually thinks that all these students gave up their cell phones.
  • My vow must have seemed to you extremely cruel, or insane.
  • The prosecution had mustered three psychiatrists to say that he wasn't insane.
  • They further found that he was no longer insane and he was released.
  • But he also has a number of beliefs that are, not to put too fine a point on it, utterly insane.
  • The apartments wander through the complexity of the building's form, so their floor plans look insane.
  • It's a perfect example of the kind of word that, if repeated often enough, will make you insane.
British Dictionary definitions for insane

insane

/ɪnˈseɪn/
adjective
1.
  1. mentally deranged; crazy; of unsound mind
  2. (as collective noun; preceded by the): the insane
2.
characteristic of a person of unsound mind: an insane stare
3.
irresponsible; very foolish; stupid
Derived Forms
insanely, adverb
insaneness, noun
Word Origin and History for insane
adj.

1550s, from Latin insanus "mad, insane; outrageous, excessive, extravagant," from in- "not" (see in- (1)) + sanus "well, healthy, sane" (see sane). Originally only of persons; of actions, from 1842. Cf. lunatic; and Italian pazzo "insane," originally a euphemism, from Latin patiens "suffering." German verrückt, literally past participle of verrücken "to displace," "applied to the brain as to a clock that is 'out of order' " [Buck]. The noun meaning "insane person" is attested from 1786.

insane in Medicine

insane in·sane (ĭn-sān')
adj.
Of, exhibiting, or afflicted with insanity.